The present invention relates to the general field of turbomachine roller bearings, and more particularly it provides a roller bearing of the type for supporting a high-pressure trunnion to rotate relative to a stationary support that is connected to a casing of a turbomachine.
In a turbomachine, the trunnion of a shaft line of the high-pressure spool is generally supported by a roller bearing to rotate relative to a stationary support that is connected to the casing.
Such a roller bearing is described with reference to FIG. 6. In this figure, the high-pressure spool of the turbomachine consists, in particular, of a high-pressure turbine disk 100 on which rotor blades (not shown) are mounted to move about a longitudinal axis X-X of the turbomachine. A shaft 102, which constitutes a trunnion of the shaft line of the high-pressure spool of the turbomachine, is secured to the high-pressure turbine disk 100 via a bolted connection 104. The high-pressure trunnion 102 is supported by a roller bearing 108 to rotate relative to a stationary support 106 that is connected to the casing of the turbomachine.
The roller bearing 108 consists of rollers 110 that are inserted between an outer ring 112 disposed adjacent to the stationary support 106 and an inner ring 114 disposed adjacent to the high-pressure trunnion 102. The outer ring 112 and the inner ring 114 constitute races for the rollers 110.
The outer ring 112 of the bearing 108 is directly secured to the stationary support 106. The inner ring 114 is mounted on an outer surface of the high-pressure trunnion 102, at its downstream end. A clamping nut 116 disposed downstream from the inner ring 114 serves to hold said inner ring axially against the high-pressure trunnion 102.
Such a roller bearing configuration presents numerous drawbacks. In particular, use of a fitted inner ring that is independent from the high-pressure trunnion increases the radial size of the roller bearing and constitutes additional weight. Moreover, the presence of a clamping nut necessary for retaining the inner ring and disposed downstream from the inner ring increases the axial size of the assembly.
In order to solve such problems, it has been envisaged to integrate the inner ring of the roller bearing directly in the high-pressure trunnion. That technique also has drawbacks. Firstly, in the event of failure of the roller bearing, it is necessary to replace the entire high-pressure trunnion, which increases costs. Secondly, the connection between the inner ring and the high-pressure trunnion is made by welding two different metals together, which is a technique that is difficult to master.